Finding the Balance​ The Effects of α-cyclodextrin, 2-hydroxypropyl-β-cyclodextrin, and cholesterol Bacteroides vulgatus and Clostridium bolteae​

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Ryan D. Himes


Atherosclerosis is a cardiovascular disease that is characterized by the hardening of arteries through the formation of cholesterol plaques. Cyclodextrins could potentially treat atherosclerosis by shrinking plaques. These cyclic oligosaccharides can make complexes with cholesterol but have also shown toxic side effects. This study looked for potential negative effects of cyclodextrins and cholesterol on gut bacteria. It was hypothesized that Bacteroides vulgatus will have decreased growth when grown in broth with cholesterol. In contrast, Clostridium bolteae will have decreased growth when grown in broth with cyclodextrins. Due to the fact that these bacteria are anaerobic, Clostridium bolteae and Bacteroides vulgatus, were grown using GAM broth under CO2. Data was collected by using a spectrophotometer to measure changes in bacterial growth throughout the growth cycle. Each bacteria was treated with one of three chemicals at one of three concentration to make a total of 9 different conditions. α-c yclodextrin, 2-hydroxypropyl-β-cyclodextrin, and cholesterol with concentrations of 1 mM, 10 mM, and 100 mM. The slopes of the log phase of bacterial growth were compared using a two tailed T-Test with α=0.05. Growth of Clostridium bolteae was significantly inhibited for most of the cyclodextrin trials and all the cholesterol concentrations. Bacteroides vulgatus growth was inhibited by 100 mM concentrations of cholesterol and α-cyclodextrins. Interestingly, Bacteroides vulgatus growth was significantly increased when grown with 1 mM and 10 mM concentrations of cholesterol. Continued research is needed to determine when cholesterol concentrations become harmful to Bacteroides vulgatus. Clostridium bolteae needs further research to understand the 10 mM α-cyclodextrin trial that did not show significant inhibition. The results demonstrate that cyclodextrins are associated with inhibited growth for these two gut bacteria but expansion of this test to other gut bacteria is key for a deeper understanding of the impact that cyclodextrins would have on the gut microbiome as a whole.


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The paper will be posted with University Honors Program in Summer 2021

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